Occlusion devices and methods

ABSTRACT

The invention provides intrafallopian devices and non-surgical methods for their placement to prevent conception. The efficacy of the device is enhanced by forming the structure at least in part from copper or copper alloy. The device is anchored within the fallopian tube by a lumen-traversing region of the resilient structure which has helical outer surface, together with a portion of the resilient structure which is biased to form a bent secondary shape, the secondary shape having a larger cross-section than the fallopian tube. The resilient structure is restrained in a straight configuration and transcervically inserted within the fallopian tube, where it is released. Optionally, permanent sterilization is effected by passing a current through the resilient structure to the tubal walls.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of pending U.S. patent applicationSer. No. 13/294,758 filed on Nov. 11, 2011, which is a continuation ofU.S. patent application Ser. No. 12/908,756 filed on Oct. 20, 2010, nowU.S. Pat. No. 8,171,936, which is a continuation of U.S. patentapplication Ser. No. 10/600,298 filed on Jun. 20, 2003, now abandoned,which is a continuation-in-part of U.S. patent application Ser. No.09/093,835, filed Jun. 8, 1998, now U.S. Pat. No. 6,705,323, whichclaims the benefit of priority from U.S. Provisional Application No.60/059,861, filed Sep. 24, 1997, and is also a continuation-in-part ofU.S. patent application Ser. No. 08/475,252 filed Jun. 7, 1995, nowabandoned, and a continuation-in-part of U.S. patent application Ser.No. 08/474,779 filed Jun. 7, 1995, now U.S. Pat. No. 6,176,240. The fulldisclosures of U.S. patent application Ser. Nos. 09/093,835, 60/059,861and 08/475,252 are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to contraception, and moreparticularly to intrafallopian contraceptive devices and nonsurgicalmethods for their delivery.

Worldwide demand exists for safe, effective methods of bothcontraception and permanent sterilization. Although a variety ofcontraception and sterilization methods are available, all of theexisting methods have limitations and disadvantages. Thus, the need foradditional safe, low cost, reliable methods of contraception andpermanent sterilization, both in developed and less developed countries,is widely recognized.

Many presently available contraception methods require significant userinvolvement, and user non-compliance results in quite high rates offailure. While the theoretical effectiveness of existing contraceptives,including barrier methods and hormonal therapies, is well established,overcoming user noncompliance to improve overall efficacy has provendifficult.

One form of contraception which is less susceptible to usernoncompliance is the intrauterine device (IUD). IUDs have been found tohave higher rates of reliability, and are effective for a longer periodof time, than most other commercially available contraceptives.Unfortunately, IUDs are also associated with serious infectiouscomplications. For this reason, the use of IUDs within the United Stateshas decreased dramatically. Additionally, IUDs are subject to unplannedexpulsion, and must be removed due to excessive pain or bleeding in apercentage of cases, further reducing the acceptance of the IUD as acontraceptive method. Interestingly, the efficacy of copper IUDs appearsto be higher than that of non-metallic IUDs. The reason for this has notbeen fully explained.

Commercially available options for permanent sterilization includefallopian tube ligation and vasectomy. These methods are surgical, aredifficult to reverse, and are not available to many people in the world.It is common knowledge that fertilization occurs in the fallopian tubeswhere the sperm and ovum meet. Tubal ligation avoids this by completeocclusion of the fallopian tubes.

It has previously been proposed to reversibly occlude the fallopiantubes, for example, by in vitro formation of an elastomeric plug, orotherwise anchoring a device on either side of the narrowest region offallopian tube, called the “isthmus.” Such fallopian tube occlusionmethods appear promising; however, an unacceptably high percentage ofthe non-surgical devices proposed to date have become dislodged duringprevious studies. Even where non-surgical intrafallopian devices haveremained in place, they have been found to be only moderately effectiveat preventing conception.

For these reasons, it would be desirable to provide effective, reliableintrafallopian devices for contraception and sterilization. It would beparticularly desirable to provide highly effective intrafallopiandevices which did not require surgery for placement. It would beespecially desirable if such devices and methods allowed easy placementof the device, but were less susceptible to being dislodged thanpreviously proposed non-surgical intrafallopian devices.

2. Description of the Related Art

The experimental use of a stainless steel intrafallopian device isdescribed in Transcatheter Tubal Sterilization in Rabbits, Penny L.Ross, RT 29 “Investigative Radiology”, pp. 570-573 (1994). Theexperimental use of an electrolytically pure copperwire as a surgicalcontraceptive intrafallopian device in rats was described in“Antifertility Effect of an Intrafallopian Tubal Copper Device”, D. N.Gupta, 14 Indian Journal of Experimental Biology, pp. 316-319 (May1976).

U.K. Patent Application Pub. No. 2,211,095 describes a uterine screwplug for blocking the fallopian tube. European Patent Application Pub.No. 0,010,812 describes a device for placement in the oviducts havingenlargements at either end for anchoring the device. The same deviceappears to be described in Netherlands Patent No. 7,810,696.

The use of tubal occlusion devices is described in “HysteroscopicOviduct Blocking With Formed-in-Place Silicone Rubber Plugs”, Robert A.Erb, Ph.D., et al., The Journal of Reproductive Medicine, pp. 65-68(August 1979). A formed-in-place elastomeric tubal occlusion device isdescribed in U.S. Pat. No. 3,805,767, issued to Erb. U.S. Pat. No.5,065,751, issued to Wolf, describes a method and apparatus forreversibly occluding a biological tube. U.S. Pat. No. 4,612,924, issuedto Cimber, describes an intrauterine contraceptive device which sealsthe mouths of the fallopian tubes.

German Patent No. 28 03 685, issued to Brundin, describes a device forplugging a body duct with a device which swells when in contact with abody fluid.

Alternative contraceptive devices are disclosed in co-pending U.S.patent application Ser. No. 08/474,779, the full disclosure of which isherein incorporated by reference.

SUMMARY OF THE INVENTION

The present invention provides intrafallopian devices and methods fortheir placement to prevent conception. The intrafallopian devices of thepresent invention are transcervically delivered and mechanicallyanchored within the fallopian tube to provide long term contraception,or alternatively permanent sterilization, without the need for surgicalprocedures or the risks of increased bleeding, pain, and infectionassociated with intrauterine devices (IUDs).

The intrafallopian devices of the present invention will often comprisea structure having a lumen-traversing region with a helical outersurface. The helical surface is mechanically anchored by a resilientportion of the structure which is biased to form an enlarged secondaryshape, preferably forming distal and proximal anchoring loops. Theanchoring loops help prevent the helical outer surface from rotating outof position, and also directly deter axial motion within the fallopiantube. In alternative embodiments, anchoring may be provided by astraight coil which is resiliently deflected by the axial curvature ofthe tortuous fallopian tube, and a radially expandable braid, malecott,or some other tubular structure may help affix the device within thefallopian tube.

The use of copper in the intrafallopian device of the present inventionimproves its efficacy as a contraceptive method. Devices formed fromplastically deformable materials, however, are less readily restrainedin the fallopian tube. Apparently, the large variation in the actualshape and dimensions of fallopian tubes does not provide reliableanchoring for a pre-formed deformable intrafallopian device. Theintrafallopian device of the present invention therefore often comprisesa resilient structure, usually a metallic coil, which includes a copperalloy or plating, ideally comprising an alloy including at least 75%copper. The coil material typically includes beryllium, zinc, stainlesssteel, platinum, a shape memory alloy, such as Nitinol®, or the like.Preferably, the coil is composed of an alloy of beryllium and copper.

Although the present device will generally result in occlusion, it neednot completely occlude the fallopian tube to prevent the meeting of thesperm and ovum. Instead, in some embodiments, the presence of the copperon the resilient structure is sufficient to provide effectivecontraception. Hence, contraception can be provided by disrupting thenormal architecture and/or function of the fallopian tube, despite thepresence of an open lumen. This concept is referred to herein as“functional occlusion”. As used herein, functional occlusion means thatthe device, when implanted in the fallopian tube, disrupts the normalarchitecture and/or functioning of the fallopian tube so as to inhibitfertilization and/or conception.

Conveniently, the present invention further comprises non-surgicalplacement of such intrafallopian devices by transcervical introduction.The resilient structure is restrainable in a straight configuration,e.g., by use of a corewire, greatly facilitating and reducing the risksof introduction. Thus, the cost and dangers associated with existingsurgical contraceptive and sterilization procedures are avoided. Theresilient structure will often comprise a coil. In some embodiments, anelement is disposed along the coil, and is adapted to incite a tissuereaction in the tubal tissues which inhibits conception. A distal anchorof the coil may be inserted into the ampulla, distal of the isthmus,while a proximal anchor is located in the ostium. These anchors preventrotation of the device, and also help avoid axial movement.Alternatively, at least one of the anchors may be positioned anywherepast the ostium and within the fallopian tube, while the other extendsinto the uterus, depending on their length and configuration.Preferably, at least some anchoring is provided along the intramural toisthmic region of the fallopian tube. In some embodiments,electrosurgical attachment of an intraluminal device to a surroundinglumenal wall may provide effective anchoring even without loops andother anchoring structures. Electrical current may also be used todecouple the intrafallopian device from the delivery system, typicallyby electrolytically dissolving a solder bond. Current may also actuatean anchor, such as by releasing a resilient radially expandable tubularstructure within the fallopian tube.

The present invention also provides improved contraceptive devices whichincite a tissue reaction within the fallopian tube to preventconception. This group of intrafallopian devices will often make use ofa highly flexible coil structure to avoid damaging or penetratingthrough the delicate tubal tissues. The desired tissue reaction may bethe result of the material of intrafallopian device, or may be incitedby a coating, a surface treatment, a mechanical interaction between thedevice and the surrounding tubal wall, or the like. The tissue willoften help impede conception by occluding the fallopian tube, byinterrupting the transport mechanisms of the tubal tissues, and/or byrestraining the intrafallopian tubal device within the tube. Specifictissue reactions which may provide these intended results include tissueingrowth into the contraceptive device and/or the tubal lumen, scartissue formation, sclerosing of the tubal tissues, and the like.

In one aspect, the invention provides a tissue reaction contraceptivedevice for use in a fallopian tube. The contraceptive device comprises acoil having a proximal end and a distal end and defining an axistherebetween. The coil is axially flexible and has a cross-sectionsuitable for insertion into the fallopian tube. An element disposedalong the coil is adapted to incite a tissue reaction in the tubaltissues adjacent the coil so as to inhibit conception.

In some embodiments, the element may promote ingrowth of the tubaltissues into the contraceptive device. For example, the element mayinclude a braided or woven polyester, a micro-porous material or surfacetreatment, or the like. Alternatively, a sharp edged helical ribbon orother mechanical interaction element may incite the formation of scartissue, or a surface coating of the coil may sclerose the tubal tissues,exciting formation of tough fibrous connective tissues which interferewith conceptive transport. In many embodiments, the presence of thecontraceptive device in combination with the tissue reaction can provideeffective contraception without having to rely on total occlusion of thefallopian tube.

In another aspect, the present invention provides a tissue ingrowthcontraceptive device for use in a fallopian tube. The contraceptivedevice comprises a tubular retention structure having a proximal end, adistal end and an axis therebetween. The retention structure is axiallyflexible, and is insertable within the fallopian tube. A material whichcan incite ingrowth of the tubal tissue is attached to, and exposedradially from, the retention structure.

In the exemplary embodiment, the retention structure comprises a helicalcoil in which the ingrowth material is disposed. Such helical coils mayoptionally be radially expansible within the fallopian tube, therebyallowing the device to accommodate a wide variety of tubal physiologies.The ingrowth material may be in the form of braided or woven fibers ofpolyester, P.T.F.E., or the like.

In another aspect, the present invention provides a tissue ingrowthcontraceptive device for use in a fallopian tube. The contraceptivedevice comprises a resilient elongate body having a proximal end and adistal end and defining an axis therebetween. A retention structure isdisposed along the resilient body. The retention structure is adapted torestrain the resilient body within the fallopian tube. A bond affixesthe retention structure to the resilient body. At least one of theresilient body, the retention structure, and the bond comprises amicro-porous material which promotes tissue ingrowth therein.

In another aspect, the present invention provides a contraceptive methodcomprising transcervically inserting a contraceptive device within afallopian tube. The device is inserting by resiliently deflecting adistal body of the contraceptive device against a tubal wall, so thatthe distal body guides the contraceptive device axially along thefallopian tube. A tissue reaction is incited with an element of thecontraceptive device in the tubal tissues. This tissue reaction affixesthe contraceptive device within the fallopian tube.

The present invention also provides improved contraceptive devices,systems, and methods adapted for use in the widely varying geometry ofthe fallopian tube. In recognition of the wide variations in tubalphysiology, the contraceptive structures of the present invention areradially expandable within the fallopian tube to engage the tubal wall.Surprisingly, the contraceptive devices of the present invention willoften make use of tubular structures such as resilient helical coils.Such tubular devices will often effect contraception by disrupting thearchitecture and/or transport mechanisms of the tubal tissues, ratherthan relying entirely on total blockage of the tube. The passagesthrough the tubular contraceptive devices of the present invention mayoptionally be occluded by promoting tissue ingrowth within the device,for example, by including woven or braided polyester fibers within ahelical coil. Regardless, such tubular retention structures are capableof radially expanding against tubal walls throughout a wide range oftubal sizes to safely anchor the contraceptive device, without having toresort to protruding barbs or the like.

In one aspect, the present invention provides a contraceptive device foruse in fallopian tube having a tubal wall. The contraceptive devicecomprises a tubular retention structure having a proximal end, a distalend, and an axis therebetween. The retention structure is radiallyexpandable in situ from a narrow configuration (in which the retentionstructure has a first diameter which is suitable for axial insertioninto the fallopian tube) so as to define a second, enlarged diameter.The expanded retention structure is adapted to engage the surroundingtubal wall and retain the contraceptive device within the fallopiantube.

In another aspect, the present invention provides a contraceptive devicefor use in a fallopian tube having a tubal wall. The contraceptivedevice comprises a conception inhibiting body which defines an axis. Ahelical coil is disposed about the body. A portion of the helical coilis movable relative to the body so that the helical coil can expandresiliently throughout a range of tubal cross-sectional sizes. Hence,the coil can radially engage the surrounding tubal wall and safely affixthe contraceptive device within the fallopian tube.

The present invention also provides intrafallopian contraceptive deviceshaving elongate coils which are substantially straight. Surprisingly,when such straight coils are positioned axially within the tortuousfallopian tubes, the bends imposed on the coil by the fallopian tube canresult in resilient anchoring of the coil. Such straight coils are alsohighly advantageous when advancing the contraceptive device into (andwithin) the fallopian tube. Straight resilient coils can act as anintegral guidewire during transcervical deployment of the device withinthe fallopian tube, thereby avoiding the delay associated with thesequential use of guidewires, tubal axis catheters, and the like.

The present invention provides an intrafallopian contraceptive devicefor use in a fallopian tube. The contraceptive device comprises anelongate coil having a proximal end, a distal end, and an axistherebetween. The axis is substantially straight when the coil is atrest, and the coil is axially resilient to facilitate insertion of thebody axially into the tube. The device is adapted to be retained withinthe fallopian tube so as to inhibit conception.

In another aspect, the present invention provides an intrafallopiancontraceptive device for use in a fallopian tube. The tube has a tubalwall with a tubal cross-section and an axial curvature. Thecontraceptive device comprises an elongate body having a proximal endand a distal end and defining an axis therebetween. The body has across-section suitable for axial insertion within the tubalcross-section. At least a portion of the body is straighter than theaxial curvature of the fallopian tube. The body is sufficiently flexibleto deflect against the tubal wall without injuring the tubal wall. Thebody is also sufficiently resilient to impose an anchoring force againstthe tubal wall when the straight portion flexes along the axialcurvature of the fallopian tube.

In another aspect, the present invention provides a contraceptive devicefor use in a fallopian tube having an axis. The contraceptive devicecomprises a structure having a proximal end, a distal end, and an axistherebetween. The structure is adapted to provide effective tubalocclusion when disposed substantially coaxially within the fallopiantube. An elongate member is affixed to the occlusion structure. Themember extends distally of the occlusion structure and is sufficientlyflexible and axially resilient to help guide distal advancement of theocclusion structure within the fallopian tube.

In a contraceptive method provided by the present invention, an elongateresilient body is transcervically inserted into an axially curvingfallopian tube so that the fallopian tube imposes an axial bend on thebody. The bent body imposes an anchoring force which helps anchor thebent body within the fallopian tube. The body is anchored within thefallopian tube so that the affixed resilient body inhibits conception.

In another aspect, the present invention provides a contraceptive methodcomprising transcervically inserting an intrafallopian contraceptivedevice along the fallopian tube by guiding the contraceptive device witha distal guidewire-like structure of the contraceptive device. Thedevice, including at least a portion of the guidewire-like structure, isretained within the fallopian tube so that the device inhibitsconception.

In another aspect, the present invention provides a contraceptive kit.The kit comprises an intrafallopian contraceptive device andinstructions for its use. The instructions describe and/or set forth themethod steps of transcervically introducing the contraceptive deviceinto a fallopian tube and affixing the contraceptive device within thetube. Optionally, a variety of delivery structures may also be providedin the kit, including guidewires, corewires, delivery catheters, and thelike.

In yet another aspect, the invention provides an intrafallopiancontraceptive system comprising an elongate delivery body having aproximal end and a distal end. A first energy conduit extendstherebetween, and an intrafallopian structure near the distal end has afirst cross-section. An energy source is coupled to the structure by thefirst conduit. Energy from the energy source reconfigures the structureto a second cross-section to restrain the structure within a fallopiantube and inhibit conception.

In a final aspect, the invention provides an elongate delivery bodyhaving proximal and distal ends with first and second conductorsextending therebetween. An intrafallopian contraceptive structure isnear the distal end of the delivery body. An electrical power supply canbe coupled to the structure by the first and second conductors. Thisadvantageous bipolar arrangement can, for example, allow actuation of ashape-memory alloy structure by transmitting current through at least aportion of the structure from a hand-held battery.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first embodiment of a contraceptive intrafallopiandevice according to the present invention.

FIG. 2 illustrates a primary coil used in the contraceptiveintrafallopian device of FIG. 1.

FIG. 3 illustrates a secondary coil which has been imposed on a primarycoil as used in the contraceptive intrafallopian device of FIG. 1.

FIG. 4 illustrates a corewire for use with the contraceptiveintrafallopian device of FIG. 1.

FIG. 5 is a cross-sectional view of a contraceptive delivery systemhaving the contraceptive intrafallopian device of FIG. 1.

FIG. 6 illustrates an alternative embodiment of the presentcontraceptive intrafallopian device.

FIG. 7 illustrates a primary coil used in the contraceptiveintrafallopian device of FIG. 6.

FIG. 8 schematically illustrates a contraceptive delivery systemincluding the contraceptive intrafallopian device of FIG. 6.

FIGS. 9 and 10 illustrate a method of delivery of a contraceptiveintrafallopian device according to the present invention.

FIGS. 11A-D illustrate intrafallopian contraceptive devices havingstraight primary coils, together with associated delivery devices andsystems.

FIGS. 12A-E illustrate a variety of intrafallopian contraceptive deviceswhich are adapted to promote a tissue reaction that enhances thecontraceptive efficacy of the device.

FIG. 13 illustrates a method for introducing a dense braid of fibermaterial into a helical coil of a contraceptive device.

FIGS. 14-14E illustrate helical coils which adapt to varying tubal sizesto enhance retention of the contraceptive device within the fallopiantube.

FIGS. 14F, 14G, and 14H show structures for releasably restraining acoil.

FIG. 15A-D illustrate cross-sectional views through the fallopian tubebefore, during, and after delivery of a contraceptive device having aradially expandable helical coil, and also illustrates the enhancedefficacy provided by tissue reactions such as tissue ingrowth into andaround the helical coil.

FIG. 15E illustrates the self-guiding capabilities of a contraceptivedevice having a straight primary coil.

FIG. 16 illustrates a contraceptive delivery system having a detachabledistal corewire.

FIG. 17 schematically illustrates a kit including a contraceptivedelivery system and instructions for its use.

FIGS. 18A-C schematically illustrate alternative tubular radiallyexpandable retention structures which can mechanically anchor acontraceptive device in the fallopian tube.

FIGS. 19A and B illustrate an intrafallopian contraceptive system inwhich a hand-held battery electrically actuates the retention structureby transmitting a current which heats a shape-memory alloy of theretention structure.

FIGS. 20A and B illustrate an intrafallopian contraceptive device andmethod for its use to support a coil comprising copper within theutero-tubal junction.

FIGS. 21A-C illustrate alternative structures comprising copper andmethods for their use to inhibit conception, according to the principlesof the present invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

The present invention encompasses a contraceptive intrafallopian devicewhich can alternatively be used as both a permanent and a reversiblemeans of contraception. The present contraceptive methods and devicesminimize the danger of non-use which has limited the efficacy of priorart contraceptive techniques. Moreover, the location of the presentdevices within the fallopian tubes provides a reduced risk of theinfectious complications, increased bleeding, and pelvic pain associatedwith intrauterine devices (IUDs). The location and the novel shape ofthe present intrafallopian device provides significant advantages overIUDs, which have been found to be susceptible to unplanned expulsion andremoval due to excessive pain and bleeding. The present invention takesadvantage of the increase in effectiveness associated with copper IUDs,providing a resilient structure including copper which may betranscervically positioned without the need for surgery.

Although the present contraceptive method is included within a group ofcontraceptive techniques generally referred to as fallopian tubeocclusion methods, the present invention does not necessarily relysolely on blocking the fallopian tube to prevent fertilization. Instead,contraception is apparently provided by disrupting of ovum transport,the process of fertilization, and/or cleavage of the ovum. While theeffect that copper has on these processes is not fully understood, itdoes appear that copper intrafallopian devices offer potentiallysignificant increases in effectiveness over intrafallopian devicesformed of other materials. Contraception may alternatively be providedor enhanced by a spermicidal agent attached to the device. Optionally,the present invention further encompasses devices which promote thegrowth of tissue within the tube to induce tubal occlusion, furtherinhibiting conception. In some embodiments, polyester fibers such asDacron®, Rayon®, or the like, are bonded to the surface of the coilusing a polymeric adhesive. The polyester fibers promote increasedtissue growth around the coil, thus further reducing the possibility ofexpulsion of the device from the fallopian tube.

Conveniently, the present resilient structures are adapted to bereleasably affixed over a corewire, the corewire restraining theresilient structure in a straight configuration. As the resilientstructure has an outer diameter when in the straight configuration whichis less than the inner diameter of the fallopian tube, the cathetercontaining the present intrafallopian device is easily transcervicallyintroduced.

The present invention may be anchored within the isthmus of thefallopian tube, overcoming the unintended expulsion of the device andthe resulting failure of the contraceptive method. Such intrafallopiandevice expulsion has been the single greatest factor limiting theefficacy of easily positioned intrafallopian contraceptive techniques.The present intrafallopian devices are generally elongate resilientstructures pre-formed into secondary shapes. These secondary shapes willpreferably form anchors proximally and distally of the narrowest portionof the fallopian tube, called the isthmus. The secondary shapepreferably has a larger outer diameter than the inner diameter of theisthmus. Anchoring may also be possible with a structure spanning otherportions of the tubal lumen, often between the ostial opening and theisthmus.

The present device is generally readily removed by snaring the resilientstructure near the proximal end and pulling proximally on the resilientstructure, thereby straightening the resilient structure and allowing itto be withdrawn without injuring the fallopian tube. Alternatively, anelectrical current is applied to the device after it is positionedwithin the fallopian tube, providing permanent sterilization. Electricalcurrent might also effect detachment of the device from the deliverysystem using a system similar to that described in U.S. Pat. No.5,624,449, the full disclosure of which is incorporated herein byreference. In situ actuation of an anchor might be effected by releasinga resilient structure to expand in situ with a similar mechanism, or bya current induced phase change of a shape memory alloy (for example,causing a straight Nitinol® ribbon to curl within the fallopian tubewith a current).

Referring now to FIG. 1, a first embodiment of the present contraceptiveintrafallopian device 10 is formed from a resilient primary coil 12.Primary coil 12 has a proximal end 14 and a distal end 16, the latterhaving an atraumatic endcap 18. Primary coil 12 further includes threeportions: a proximal anchor portion 20, a distal anchor portion 22, anda lumen-traversing region 24. Proximal and distal anchors 20, 22 arebiased to form anchoring loops 26, as described hereinbelow.

Lumen-traversing region 24 comprises a substantially straight portion ofprimary coil 12. A ribbon 28 is wound over the outer surface of primarycoil 12 to provide a helical shape. Ribbon 28 includes sharp outer edges29, which firmly anchor lumen-traversing region 24 in the fallopian tubewall when torque is applied to intrafallopian device 10. The ribbon ispreferably formed of a high strength biocompatible metal, ideally beingstainless steel. The ribbon is attached to primary coil 12 at a proximaljoint 30 and a distal joint 32, which may be formed of solder,heat-shrink tubing, or the like.

Referring now to FIG. 2, primary coil 12 is most easily formed in astraight configuration as a cylindrical coil or spring, preferablyhaving an outer diameter in the range from 0.005 inch to 0.05 inch, andhaving a length in the range from 20 mm to 150 mm. Ideally, primary coil12 has an outer diameter in the range from 0.01 inch to 0.05 inch and alength in the range from 30 mm to 125 mm.

Preferably, primary coil 12 is formed from a beryllium copper alloywire. Beryllium copper provides the resilience necessary to avoidexpulsion of the device, and also provides the increased effectivenessof a copper contraceptive intrafallopian device. Such a beryllium copperwire will typically have a diameter from 0.002 inch to 0.01 inch. Toprovide the increased efficacy of a copper intrafallopian device,primary coil 12 preferably comprises an alloy including 75% copper.Alternatively, primary coil 12 is formed from a resilient metal, such asstainless steel, platinum, a shape memory alloy, or the like. If suchmaterials are used, primary coil 12 is preferably plated with copper ora copper alloy or otherwise has copper attached.

Primary coil 12 includes a body winding 42 and a thread winding 44. Bodywinding 42 is formed with the minimum possible pitch to increase thestiffness of primary coil 12. Thread winding 44 will typically comprisefrom 0.1 cm to 2.0 cm adjacent to proximal end 14, and will have a pitchroughly twice that of body winding 42.

Referring now to FIG. 3, the proximal and distal anchors are formed byimposing a bent secondary shape on selected portions of primary coil 12.The secondary shape preferably comprises loops 26 formed by bendingprimary coil 12, and heat treating the primary coil while it is bent. Awide variety of secondary shapes may be used, including sinusoidalcurves, alternating loops, or loops separated by straight sections so asto form a “flower coil,” as more fully described in co-pending U.S.patent application Ser. No. 08/474,779, the full disclosure of which isherein incorporated by reference. In most cases, the bent secondaryshape will have an outer cross-section 46 which is larger than thefallopian tube to provide effective anchoring.

Referring now to FIG. 4, a corewire 50 for use with intrafallopiandevice 10 (FIG. 1) comprises a resilient wire 52 which tapers towards adistal end 54. Wire 52 is sufficiently stiff to restrain intrafallopiandevice 10 in a straight configuration, typically comprising stainlesssteel, platinum, or the like. A short section of coil forms corewirethreads 56 attached at threadjoint 58. Threads 56 match the windings andpitch of threadwindings 44 of primary coil 12.

Referring now to FIG. 5, an intrafallopian contraceptive system 60comprises corewire 50 inserted within a lumen 62 through intrafallopiandevice 10. Intrafallopian device 10 is releasably attached by engagingthread windings 44 with threads 56. Thus, intrafallopian device 10 isdisengaged by torquing a proximal end of corewire 50 once intrafallopiandevice 10 is in position.

Referring now to FIG. 6, an alternative embodiment of the presentintrafallopian device is again formed from a resilient primary coil 112having a proximal end 114 and a distal end 116. The former includes afriction fitting 115. Primary coil 112 again includes three portions: aproximal anchor portion 120, a distal anchor portion 122, and alumen-traversing region 124. Proximal and distal anchors 120, 122 arehere biased to form opposed anchoring loops 26, thereby increasing therelaxed overall cross-section of the proximal and distal anchors. Aribbon 128 is wound over the outer surface of primary coil 112 toprovide a helical shape, as described above.

Referring now to FIG. 7, primary coil 112 comprises a uniform bodywinding 142. The secondary shape is imposed on the straight cylindricalcoil as opposed loops 126, or alternatively as multiple loops of aflower coil.

Referring now to FIG. 8, an intrafallopian contraceptive system usingalternative intrafallopian device 100 includes a corewire 152 whichtapers towards a distal end 154. Friction fitting 115 fittingly engagescorewire 152, which restrains primary coil 112 in a straightconfiguration. A release catheter 164 is slidably disposed over corewire152 proximally of alternative intrafallopian device 100, allowing thedevice to be released by withdrawing corewire 152 relative to therelease catheter.

Use of the present contraceptive intrafallopian device will be describedwith reference to FIGS. 9 and 10. A uterine introducer canula 70 isinserted transcervically through a uterus 72 to the region of an ostium74. Alternatively, a hysteroscope may be used in place of canula 70, oran echogenic and/or radiopaque device might be placed under sonographicor radiopaque guidance.

Intrafallopian contraceptive system 60 is advanced distally ofintroducer cannula 70 and maneuvered through the fallopian tube,preferably until intrafallopian device 10 extends distally of theisthmus. Optionally, intrafallopian contraceptive system 60 isself-guided, with corewire 52 bent near distal end 54 to assistintraluminal maneuvering. Alternatively, a guide wire and catheter areadvanced into the fallopian tube first, and the guide wire is replacedwith intrafallopian contraceptive system 60. In either case, theintrafallopian device will generally be axially positioned withlumen-traversing region 24 within a target region 84 adjacent to isthmus80. Preferably, at least one loop of distal anchor 22 is distal oftarget region 84, and at least one loop of proximal anchor 20 isproximal of target region 84 to form the distal and proximal anchorbends.

Once intrafallopian device 10 is properly positioned, corewire 50 istorqued to set ribbon 28 in the tubal wall. The corewire may then beunthreaded from intrafallopian device 10 by rotating the corewire in theopposite direction, disengaging threads 56 from thread windings 44. Thecorewire is then free to slide proximally, releasing the primary coil.As the distal end of the primary coil is released, a distal anchor bend90 is formed. Similarly, a proximal loop forms a proximal anchor bend92. The anchor bends help to axially restrain the device within thefallopian tube, and also prevent rotation around the helical shape oflumen-traversing region 24. As seen in FIG. 10, the loops need notassume their relaxed form to provide effective distal or proximalanchors.

The present invention further encompasses permanent sterilization bypassing a current through the corewire to the intrafallopian deviceprior to withdrawing the corewire. Fallopian tube tissue in contact withthe intrafallopian device is desiccated, and thus attached to thepresent intrafallopian device. This action also causes permanent tubaldamage, leading to the formation of scar tissue which encapsulates theintrafallopian device and causes permanent occlusion of the tubal lumen.Clearly, the corewire/primary coil interface must be conductive to allowthe present non-surgical method of permanent sterilization.

The intrafallopian contraceptive methods and devices of the presentinvention can provide highly effective contraception even when thecontraceptive device does not totally occlude the lumen of the fallopiantube. To minimize distention of the delicate tubal tissue, the presentinvention will often leave some open lumen within the fallopian tube, atleast when initially deployed. In fact, these contraceptive devices willoften comprise perforate tubular structures having lumens. Nonetheless,contraception can be provided by disrupting the normal architectureand/or function of the fallopian tube, despite the presence of an openlumen. This concept is referred to herein as “functional occlusion”. Asused herein, a device which provides functional occlusion means that thedevice, when implanted in the fallopian tube, disrupts the normalarchitecture and/or functioning of the fallopian tube so as to inhibitfertilization and/or conception.

The size of an occlusive device required to provide functional occlusionmay depend on the material of the device, the position the device is tobe deployed within the fallopian tube, the interaction between thedevice and the surrounding tubal wall, and the like. For example,intrafallopian contraceptive structures which include fibers ofpolyester may incite ingrowth of the tubal tissues into the device. As aresult of this tissue/device interaction, a relatively small devicewhich promotes ingrowth may be capable of providing effective occlusion.In fact, such a device may be capable of providing total occlusion byinciting sufficient ingrowth so that the hyperplastic tubal walls, incombination with the device, block all passage through the tubal lumen.Hence, relatively small, easily inserted structures may effectivelyinhibit conception without the danger of distending the tubal wall.

One easily inserted intrafallopian contraceptive structure which may becapable of providing effective tubal occlusion is illustrated in FIG.11A. A straight contraceptive device 200 includes a straight primarycoil 202 around which is disposed a secondary helical coil 204 asdescribed above. Secondary coil 204 is affixed to primary, coil 202 at apair of bonds 206. As illustrated above in FIG. 6, the secondary helicalcoil may have an inner surface which is larger than the outer surface ofprimary coil 202, which may facilitate embedding the corners of thesecondary coil in the surrounding tubular wall. However, unlike theintrafallopian devices described hereinabove, straight device 200remains substantially straight between a proximal end 208 and a distalend 210 when the primary coil is at rest.

Primary coil 202 will typically be formed from wire having a diameter ofbetween about 0.002 and 0.009 inches, by winding the wire to form a coilhaving a diameter between about 0.010 and 0.040 inches. Primary coil 202will often have a length of between 2.9 and 3.5 cm. The ribbon used toform secondary helical coil 204 will generally have a width betweenabout 0.005 and 0.020 inches, and a thickness of between about 0.0005and 0.005 inches.

In the exemplary embodiment, straight device 200 includes a primary coil202 having a total length of between about 3.0 and 3.35 cm. Theexemplary primary coil 202 is wound from platinum wire, the platinumwire having a thickness of 0.005 inches, which is wound to provide aprimary coil having an outer diameter of about 0.018 inches and a lengthof about 3.0 cm. Secondary coil 204 is formed from a platinum ribbonhaving a width of 0.012 inches and a thickness of 0.002 inches. Bonds206 comprise gold solder and secondary coil 204 has a length of about0.5 to 1.0 cm and an outer diameter of between about 0.035 to 0.040inches when affixed to the primary coil 202. Solder is also used to forman atraumatic tip at distal end 210.

Referring now to FIGS. 11B and 11C, a self-guiding contraceptivedelivery system 212 includes straight contraceptive device 200 and aflexible tip corewire 214. As described above, threads 216 on flexibletip corewire 214 mate with the proximal end 208 of straightcontraceptive device 200, the threads ideally comprising a stainlesssteel coil having approximately the same dimensions as primary coil 202and affixed to the corewire with yet another gold solder joint 206.

Advantageously, distal end 218 of corewire 214 need not have sufficientstiffness and strength to restrain a coil biased to form a bentsecondary shape. As a result, the thickness of corewire 214 may beoptimized to enhance the trackability and pushability of self-guidedcontraceptive system 212, thereby enhancing the ability of thecontraceptive system to act as its own guidewire.

Delivery of the contraceptive device is facilitated by using a corewirehaving a relatively long, stiff proximal section and a relatively short,flexible section, the flexible section typically being tapered asillustrated. The thickness and material properties of these sections areselected to provide enough column strength to allow corewire 214 toadvance straight device 200 within the fallopian tube, but enoughflexibility at the distal end of the delivery system for distal end 210to navigate the tortuous fallopian tube. A relatively thick proximalsection also improves the torque transmission capabilities of the wire,particularly for torquing and embedding the outer coil against the tubalwall.

Proximal section 220 of corewire 214 will preferably be flexible enoughfor delivery through a flexible catheter and/or through the workingchannel of an endoscope. The corewire will generally comprise a materialwhich resists kinking and resiliently returns to its original shape,ideally comprising a shape memory alloy such as Nitinol® or a treatedstainless steel. Such resilience may be tailored to enhance the abilityof the delivery system to access the tubal ostium and advance thecontraceptive device into the fallopian tube. In some embodiments,corewire 214 will be capable of transmitting heat, electrical current,and/or some other energy which induces scarring, electrocautery, or thelike, so as to attach the contraceptive device within the fallopiantube. Alternatively, the transmitted energy may decouple the device fromthe corewire, for example, by melting a coupler.

In a particularly advantageous aspect, threads 216 of delivery system200 may be adapted to enhance visualization of the detachment process.For example, a first portion of the threads 222 may be a first color(such as green) while a second portion of the threads 224 may be asecond color which contrasts sharply with the first color (such as red).As they are near the proximal end of the device, threads 216 will oftenbe more visible than the remainder of the contraceptive device. Thethreads may even protrude through the tubal os into the uterus forviewing through the hysteroscope. By visually monitoring highlycontrasting colors of the thread portions through the hysteroscope, theattending physician will be provided with direct feedback on thedecoupling process. The thread portions may be colored by coating,anodizing, oxidation, polishing, the use of differing materials, or thelike. A stripe or other mark may also be provided on the delivery wireto help monitor rotation. Alternative embodiments may use threads havinghigh contrast under imaging.

Still further capabilities may be incorporated into the delivery system.For example, a “smart” delivery device may be able to sense its positionwithin the fallopian tube magnetically, electrically, optically,ultrasonically, or the like. Similarly, the deployed device mayincorporate structures which allow the physician to remotely verify theposition and presence of the device without having to access thefallopian tube (e.g., using a magnetic sensor, impedance, and/or radioactivity).

In the exemplary embodiment, corewire 214 comprises a shape memory alloysuch as Nitinol®. Proximal portion 220 of corewire 214 has a thicknessof between about 0.018 and 0.040 inches, ideally being about 0.035 cm,and the corewire tapers over a length of about 5.0 cm to a minimumthickness of between about 0.002 and 0.008 inches, typically about 0.003inches at distal end 218.

One method for attaching polyester fibers 226 to straight contraceptivedevice 200 is illustrated in FIG. 11D. As described above, suchpolyester fibers promote tissue ingrowth, which can help affix thedevice within the fallopian tube. Additionally, such tissue ingrowth mayalso help to further occlude the lumen of the fallopian tube. Fibers 226are shown tied in loops around the secondary coil, ideally using betweenabout 5 and 7 loops and fiber.

A wide variety of alternative mechanisms may be employed to incite atissue reaction which enhances the functional occlusion of theintrafallopian contraceptive device. For example, materials such ascollagen, hydroxyapatite, solid or fibrous PTFE, or the like may beused. Biodegradable coatings may cause tissue ingrowth or scarring, andthen degrade to leave a fully or partially occluded lumen. In someembodiments, the engagement between outer coil 204 and the tubal wallinjures the epithelial tissues, and the healing process results in theformation of scar tissues which interfere with the functioning of thefallopian tube.

A variety of alternative ingrowth promoting intrafallopian contraceptivedevices are illustrated in FIGS. 12A-E. Generally, each of these devicesincludes some element which promotes ingrowth of tubal tissues therein.A porous secondary coil 230 may be formed of a porous metal, ideallycomprising a micro-porous shape memory alloy such as Nitinol®. In someembodiments, ingrowth bonds 232 may be formed of, or coated with, amaterial such as bioglass, ceramics, or the like so as to promote tissueingrowth, so that the entire device may promote ingrowth. Surfacetreatments may also encourage ingrowth. For example, blasting a surfacewith small particulates can create a somewhat devoted and poroustexture. Such porous textures at the surface, with micron-sized pores,may produce the desired tissue reaction. Alternative embodiments mayinclude an open cell ingrowth promoting structure, such as the open cellfoams used to attach some breast implants.

In some embodiments, discrete bodies 234 may be formed as rings orannular beads using any of the above listed tissue ingrowth materials,coatings, or treatments. Wound, wrapped, or braided fiber material 236may also be disposed between the primary and secondary coils, the fibermaterial typically comprising a polyester such as Dacron®, Vicril®, orthe like. Dense fiber materials within the device may enhance thereaction and/or ingrowth of the surrounding tubal tissues, and alsodecreases the amount of open space within the device, thereby minimizingany prosthetic lumen. Fiber material 236 may also be in the form of athick felt, or may simply be spun with several layers of windings.

Still further alternative ingrowth promoting elements are possible, suchas tubular fabric 238 of felt, braided or woven material, or the like.Tubular fabric 238 provides an open conduit at the proximal end of thedevice to avoid impeding with the removal of the corewire, and the outerdiameter of the tubular fabric will preferably be less than the outerdiameter of the secondary coil. In some embodiments, simply providing aninternal fabric 240 in the form of a textile mesh or felt inside theprimary coil may be sufficient to incite ingrowth of the tubal tissuesinto the coil, affixing the coil in place and providing functionalocclusion of the fallopian tube.

Referring now to FIG. 13, a particularly advantageous method forproducing a contraceptive device having a dense fiber braid 250 isillustrated. Dense fiber braid 250 is initially formed by wrappingseveral layers of fiber around a mandrel. After about fifteen layers offiber have been wrapped over the mandrel, the wound fiber is slid offthe mandrel, and the windings are processed to form the braid. The braidis affixed to contraceptive device 200 adjacent one of the bonds, andthe fiber braid is then wound between the windings of secondary coil204. As a result, at least a portion of fiber tube 250 is disposed inthe annular space between the primary coil and secondary coil 204. Oftentimes, some portion of the fiber will also extend radially beyondsecondary coil 204, as illustrated.

The use of dense fiber braid 250 provides a much greater amount of fiberand a more radially compact, easily deployable assembly than a structurewhich includes loops tied radially around the secondary coil. Suchdensely packed fiber thereby makes use of an otherwise open space, andthe enhanced amount of fiber should provoke a more robust tissuereaction. Specifically, dense fiber braid 250 will have a smaller poresize, which is generally advantageous for tissue ingrowth. Thiscombination of an enhanced tissue reaction, with a less axially opendesign, would appear to provide significant advantages for functionalocclusion of the fallopian tube.

A still further alternative intrafallopian contraceptive device 200′ isillustrated in FIG. 14. Alternative device 200′ includes several of thesame primary structures described hereinabove regarding straightcontraceptive device 200, but makes use of a fiber tube 252 to providethe advantages of high fiber density and a small radial package. In thisembodiment, the fiber is again wrapped around a mandrel several times(ideally about 15 times) and then removed as a fiber tube. Tube 252 isslid off the mandrel and onto the primary coil. The tube may bepositioned before or after secondary coil 204 is attached at bond 206,and will generally occupy the annular space between the primary andsecondary coils. The ends of tube 252 can be tied to keep the tube inposition during delivery.

Alternative contraceptive device 200′ also differs from the previousstructures in that secondary coil 204 has a free end 254 which is notaffixed to primary coil 202. As free end 254 can move relative toprimary coil 200, secondary coil 204 can expand radially well beyondbond 206, and can also be radially compressed to provide a very smallouter diameter during delivery of the device. Hence, the diameter ofsecondary coil 204 in alternative device 200′ provides a highly radiallyvariable tubular structure which can easily adapt to a wide variety oftubal lumen cross-sectional sizes to retain the contraceptive devicewithin the fallopian tube.

A highly radially expandable tubular retention structure has severalsignificant advantages. First, the structure can be inserted in a narrowprofile configuration and radially expanded within the fallopian tube toprovide a secure anchor with minimal danger of protruding through thedelicate tubal wall. Additionally, the stiffness of the helicalsecondary coil can be tailored to provide the appropriate engagementforce and/or damage to the wall tissue so as to provoke the desiredtissue reaction, whether it be scar tissue formation, ingrowth, or thelike. Torquing of a free ended helical coil may also be used to adjustthe outer diameter during delivery.

The enhanced variability in outer diameter provided by an outer coil 204having a free end 254 can be understood with reference to FIGS. 14A-C.Generally, outer coil 204 will here have an outer diameter of over about0.080 mm in its relaxed state, the outer diameter of the secondary coilpreferably being biased to form a helix with an outer diameter of about1.0 mm when at rest, and will ideally be compressible to an outerdiameter of 0.1 mm for insertion. Outer coil 204 of alternative device200′ may be easily radially compressed by drawing free end 254proximally away from bond 206, by wrapping the free end around primarycoil 202, or by some combination of both.

As illustrated in FIGS. 14B and C, the device may be restrained in asmall diameter configuration by a delivery catheter 256, byarticulatable jaws 258, or the like. Regardless, secondary coil 204 willgenerally be restrained until the device is positioned within thefallopian tube, and will then be released in situ by axially withdrawingcatheter 256, articulating jaws 258, or the like. Still furtheralternative in situ release mechanisms are possible, such as dissolvingor dissipating a crystal or electrolytic coating which radiallyrestrains the secondary coil, a phase change in a shape memory alloy, orthe like, as described above. It should be noted that the free endedsecondary coil is illustrated in FIGS. 14A-C without the optional densefiber tube of FIG. 14A for clarity. Nonetheless, the enhanced radialvariability provided by a free ended helical coil (or by other perforatetubular structures) may be either used alone or combined with othertissue reaction structures described hereinabove to provide functionalocclusion and contraception.

Alternative helical retention structures are illustrated in FIGS. 14Dand 14E. A tapered coil 203 may be advanced distally, either axially orby rotationally threading the device, to embed the structure into atapering portion of the tubal wall. The device can accommodate a varietyof tubal sizes, as it need only be advanced until proper engagement hasbeen achieved. Variable stiffness along the outer coil may be providedby a coil formed with a tapering ribbon 207, or the like.

Alternative structures for releasably restraining secondary coil 204 areillustrated in FIGS. 14F-H. In the embodiments of FIGS. 14F and G,corewire 152 is rotationally coupled to primary coil 202, and hence tothe distal portion of secondary coil 204 by bond 206 (see FIG. 14C). Atab 259 is affixed to a proximal end of secondary coil 204, the tabpreferably protruding radially inwardly from the coil, the tab ideallycomprising a small diameter annulus or collar having an axis parallel tothe secondary coil axis. Tab 259 is releasably received by a keyholeslot 257 in delivery catheter 256. The tab is axially restrained in theslot when the tab engages one side of the slot, but is free to slideaxially from the slot when rotationally disengaged or pressed againstthe other side.

Prior to delivery, secondary coil 204 is restrained in a small diameterconfiguration by engagement between tab 259 and slot 257. Secondary coil204 is tightly wound down, so that the secondary coil biases the tabtoward the restrained position. The proximal portions of the corewireand delivery catheter can be rotationally affixed to each other (ideallyby a Tohey-Borst valve) to restrain the device in the smallconfiguration. This may also prevent distal movement of thecontraceptive device from the catheter and corewire.

Once the device is positioned, allowing the proximal portions of thecorewire and catheter to rotate relative to each other (by releasing theTohey-Borst valve or the like), and/or actively rotating one of thesestructures, can unwind the secondary coil and allow tab 259 to slideaxially free of the catheter. Optionally, as shown in FIG. 14G, analternative keyhole slot 263 having an angled or radiused proximalsurface may be used to urge tab 259 toward a release portion 261 of theslot by pushing the surface distally against the tab.

Still further release mechanisms are possible, including the systemillustrated in FIG. 14H. A proximally inwardly tapering body or brake265 is affixed to primary coil 202, and is fittingly received by atapering receptacle at the distal end of delivery catheter 267 when aproximal portion of secondary coil 204 is disposed therebetween.Secondary coil 204 may optionally be held in its wound-downconfiguration at the proximal end of the delivery system by aTohey-Borst valve, and can be released to unwind by moving the catheterproximally relative to corewire 152 (and hence primary coil 202 and body265), and/or by releasing the Tohey-Borst valve.

The use of a tubular, radially expandable intrafallopian device, andalso the significance of tissue reaction in providing functionalocclusion, can be further understood with reference to FIGS. 15A-D. Alumen L of a fallopian tube F is largely a potential space, much like adeflated balloon. Tubal wall W can expand around structures which areinserted into lumen L, such as around catheter 256 which radiallyrestrains a free ended secondary coil 204. Hence, the size of theirregular lumenal cross-section may be measured by the diameter of adevice it can accommodate.

Work in connection with the present invention has found that fallopiantubes can vary significantly in inner lumen cross-sectional sizes. Themaximum diameter of a device which a fallopian tube can accommodate atits smallest point can range anywhere from 0.2 to 1.5 mm. For deviceshaving a fixed cross-section, relatively large diameters will make thedevice more difficult to deliver. However, if the device is made toosmall, it can be more easily ejected from the fallopian tube. Whilefixed cross-sectional devices may still be effective (for example, byproviding a range of different device sizes), the use of a radiallyexpandable tubular structure such as free ended helical coil 204 allowsthe device to compensate for the substantially anatomical differencesbetween users.

As generally described above, catheter 256 may optionally be positionedby first accessing the fallopian tube with a guidewire, and thenadvancing the catheter over the positioned guidewire. Alternatively, thecatheter and contraceptive device may be advanced distally using thedistal end of the primary coil as a guidewire. Regardless, once thecontraceptive device is positioned at the desired axial location(generally from adjacent the isthmus to the intraluminal region, butoptionally anywhere from the corneal area to adjacent the distalfimbria), catheter 256 is withdrawn proximally while restraining thecontraceptive device axially with the proximal end of corewire 214. Ascatheter 256 is withdrawn, secondary coil 204 expands radially andengages the surrounding tubal wall W, as illustrated in FIG. 15C.Secondary coil 204 may optionally be torqued against the surroundingtubal wall from the proximal end of corewire 214, after which thecorewire is unthreaded from the contraceptive device and removed.

Although the tissues of the tubal wall protrude between the windings ofsecondary coil 204, a significant portion of lumen L remains open.Nonetheless, functional occlusion is provided so long as the deployeddevice adequately interferes with fertilization so as to inhibitconception. Functional occlusion may be enhanced by the formation ofscar tissues and the growth of tissues from the tubal wall so as toocclude lumen L (ideally both inside and outside of the tubularretention structure), as illustrated in FIG. 15D. Such scar tissueformation will also aid in anchoring the device.

As can be understood with reference to FIG. 15D and FIG. 16, open areaswithin the contraceptive device along the axis of fallopian tube F canpresent some risk of providing a passageway for fertilization. To avoidproviding a prosthetic lumen defined by the inner surface of primarycoil 202 after corewire 214 is removed, a detachable delivery wire 260is formed in two pieces. Distal delivery wire 264 is coupled to 10proximal delivery wire 262 by a threaded fastener 266. Fastener 266provides column strength to the detachable delivery wire. This allowsthe distal portion of the delivery wire to remain within the primarycoil when the contraceptive device is detached. Clearly, a wide varietyof coupling mechanisms might be used. Advantageously, a threaded couplerallows the device to be torqued in one direction and detached byrotating the proximal delivery wire 262 in the other direction,generally as described above.

The use of primary coil 202 (in combination with corewire 214) as aguidewire can be understood with reference to FIG. 15E. The goodproximal column strength of the corewire and the distally increasingflexibility of the combined corewire and primary coil at the distal endof the delivery device greatly facilitates axially advancing the devicewithin fallopian tube F. The ability of the corewire 214 to transmittorque can also help advance the delivery system distally, as well asallowing the user to embed secondary coil 204 into the surrounding tubalwall. As can also be understood with reference to FIG. 15E, the use of astraight primary coil in a portion of the fallopian tube havingsignificant axial curvature results in resilient engagement of the coilagainst the tubal wall, and can thereby provide anchoring similar tothat described above for pre-bent coils in straight lumens.

Referring now to FIG. 17, a kit 300 includes contraceptive system 212(in which straight contraceptive device 200 is mounted on corewire 214)within a sterile package 302. Also included in kit 300 are instructions304, the sterile package and instructions being disposed in packaging306. The instructions may set forth any of the method steps for using acontraceptive system as described hereinabove. Delivery system 212 maybe protected by a protective sheath 308, and other system componentsdescribed hereinabove may also be included. Also visible in FIG. 17 isthe proximal torquable handle 310 of the delivery system.

Instructions 304 will often comprise printed material, and may be foundin whole or in-part on packaging 306 or sterile packaging 302.Alternatively, instructions 304 may be in the form of a recording diskor other computer readable data, a video tape, a sound recording, or thelike.

Alternative radially expandable retention structures are illustrated inFIGS. 18A through C. A slotted tube retention structure 320 can shortenand expand within the fallopian tube. In general, such expansion may bethe result of external forces (such as actuation of a two part deliverysystem 322), or the retention structure may self-expand when released insitu. Forcibly expanded retention structures may have a latchingmechanism which prevents collapse when the device is detached from thedelivery system in the fallopian tube, and such detachment may beeffected by any of the mechanisms described hereinabove.

Still further alternative retention structures may be used in place ofhelical secondary coil 204 and slotted tube 320. For example, a Malecottretention structure 324 or a braided filament retention structure 326might be expanded to engage a surrounding tubal wall. In some cases,tubal anchoring may be enhanced by including two or more retentionstructures, or by providing small barbs which extend axially and/orradially from the expanded retention structure to prevent axialmigration. Preferably, such barbs would be too short to perforatethrough the tubal wall. A wide variety of alternative radiallyexpansible structures which might be adapted for use as a retainingstructure in the present intrafallopian contraceptive device aredescribed with reference to vascular stents.

An intrafallopian device having a retaining structure comprising a shapememory alloy is illustrated in FIGS. 19A and B. In general, the systemapplies energy to the contraceptive device so that the device expandsfrom a low profile (for delivery) to a deployed profile so as to holdthe device in place. The device may be heated by transmitting Currentalong two electrically isolated conductors to primary coil 202. Corewire152 here has an insulating layer 271 and is coupled to a first portionof the coil, while a conductor 269 in delivery catheter 256 is coupledto another portion of the coil. The resistance of the coil to a smallcurrent is sufficient to heat and reconfigure the retaining structure.Electrical energy from a common 9-volt hand-held battery within energysource will be sufficient to reconfigure secondary coil 204, which willgenerally remain in the deployed configuration at body temperature.Alternative energizing systems may use heated saline or the like.

As described above, copper may enhance the efficacy of an intrafallopiancontraceptive device 400. A1 illustrated in FIGS. 20A and B, a copperbody (for example, in the form of copper coil 402) may extend proximallyinto and/or through the utero-tubal junction from the fallopian tube. Ascan be seen in FIGS. 21A and C, the copper may alternatively be in theform of copper beads 404, which may be used to form bonds, ingrowthstructures, or the like. The copper may be in the form of a plating 406over a core material 408 for use in the primary coil, secondary coil, orthe like.

The release rate of copper is often closely related to the surface areaof copper on the device. A total copper surface area over 100 mm2, andmost often in a range from about 300 mm2 to about 400 mm2 will bepreferred to provide contraception.

The total volume of copper will affect the duration of the enhancedefficacy the copper provides. To provide lifelong contraception, weshould provide sufficient copper for about 25 years (based on thefertility life of a woman). For an exposed copper surface area of 400mm2, average copper release rates may be about 25 micrograms per day,based on intrauterine device studies. To allow our intrafallopiancontraceptive devices to release copper at this rate for 25 years, wewill preferably include at least 0.23 grams or 25.6 mm3 of total copper.To provide a reasonable safety factor, a 25-year device may include atleast about 0.34 grams or 38.4 mm2 of copper volume. These quantitiesmay be provided by each device, or by two devices (in the left and rightfallopian tubes) in combination. Similar calculations may be performedfor year devices (using the same exposed area and at least ⅕ of theabove volume), or to adjust for differing release/areal efficacyresulting from the copper structures being carried in different regionsof the fallopian tubes.

In conclusion, the present invention provides a contraceptiveintrafallopian device which may be positioned without surgery. While theabove is a complete description of the preferred embodiments of theinvention, various alternatives, modifications, and equivalents may beused. For example, a wide variety of secondary shapes, including openloops, continuous bends, sinusoidal curves, or the like, may be imposedon the primary coil. Additionally, aspects of these intrafallopiancontraceptive devices which are described separately may often becombined (for example, a self-guiding device may also promote ingrowthto affix the device in the fallopian tube). Therefore, the abovedescription should not be taken as limiting the scope of the invention,which is defined instead solely by the appended claims.

What is claimed is:
 1. A contraceptive device comprising: a resilientprimary coil, when in a relaxed state, comprising: a proximal anchor ofthe primary coil bent into a proximal secondary loop having a proximalcross-section; a distal anchor of the primary coil bent into a distalsecondary loop having a distal cross-section; and a lumen-traversingregion of the primary coil extending between the proximal anchor and thedistal anchor, the lumen traversing region of the primary coil having across-section which is smaller than both the proximal cross-section andthe distal cross-section.